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AM620-Q1: 4GB DDR - unable to access upper 2GB

Jim Meyer
Intellectual 400 points
Part Number: AM620-Q1
Other Parts Discussed in Thread: SK-AM62B-P1

Tool/software:

I've been advised that moving to "ti-processor-sdk-linux-am62xx-evm-10.00.07.04-Linux-x86-Install.bin" from v9 will allow me access to 4GB DDR.  I'm able to boot the base image on a custom board (with a number of device tree changes).  I am not able to access the upper 2GB of DDR using the u-boot utilities (mm, md), however.

  • 0
    TI__Guru**** 152541 points

    Hi Jim,

    Jim Meyer said:
    I've been advised that moving to "ti-processor-sdk-linux-am62xx-evm-10.00.07.04-Linux-x86-Install.bin" from v9 will allow me access to 4GB DDR.

    Do you have a reference to this advise? I am not aware of anything special in SDK10.0  for 4GB DDR access itself. I thought 4GB DDR should have been supported in SDK9.x too.

    However, since the SK-AM62B-P1 EVM has only 2GB DDR, the U-Boot DDR config for the EVM is only for 2GB, you would have to update the DDR config for the 4GB DDR on your custom board.

  • 0 in reply to Bin Liu
    Intellectual 400 points

    Bin,

    I originally got that information from Andreas.  Our DDR config (as far as I know) is configured for 4 GB.  I was able to boot with v10 and it appears I can access all DDR but ethernet is disabled (a config issue, I'm working on with another TI representative).

    Our DDR file is "k3-am62x-sk-ddr4-1600MTs.dtsi".  I kept the original name but the contents is for our custom board.  Are you referring to another file?

  • 0 in reply to Jim Meyer
    Intellectual 400 points

    Bin,

    Here's the u-boot utilities output on v10:

    How do you exit "mm".  I have to do ^C twice.

    From the data sheet, these seem to be within the two ranges of 2GB DDR.

  • 0 in reply to Jim Meyer
    TI__Guru**** 152541 points

    Jim,

    Jim Meyer said:
    I was able to boot with v10 and it appears I can access all DDR but ethernet is disabled

    Your first post says you are unable to access upper 2GB, but now you say you can access all 4GB. What is the difference between the two cases?

    Jim Meyer said:
    Our DDR file is "k3-am62x-sk-ddr4-1600MTs.dtsi".  I kept the original name but the contents is for our custom board.  Are you referring to another file?

    No, I was referring this file which is for DDR config.

    Jim Meyer said:
    How do you exit "mm".  I have to do ^C twice.

    I guess ^C is the only solution. I typically use mw command instead of mm.

  • 0 in reply to Bin Liu
    Intellectual 400 points

    Bin,

    I think it was a matter of properly modifying the device tree files.  It seems like it's working now.  Are those the correct address ranges? (0x80000000 - 0x100000000) && (0x880000000 - 0x900000000)

    Also, I was told (by one of your co-workers) to modify the defconfig file and rebuilt the kernel and now my ethernet is running again.

  • 0 in reply to Jim Meyer
    TI__Guru**** 152541 points

    Jim,

    Yes, this is what I expected in U-Boot device tree for 4GB DDR. Since the SK-AM62B-P1 has only 2GB DDR, its DDR size config in k3-am62x-sk-common.dtsi:

            memory@80000000 {
                bootph-pre-ram;
                device_type = "memory";
                /* 2G RAM */
                reg = <0x00000000 0x80000000 0x00000000 0x80000000>;
        };

    If your board has 4GB DDR, you would have to add another "reg" entry for the second DDR region, similar to that in k3-am62a7-sk.dts which is for SK-AM62A which has 4GB DDR:

            memory@80000000 {
                device_type = "memory";
                /* 4G RAM */
                reg = <0x00000000 0x80000000 0x00000000 0x80000000>,
                      <0x00000008 0x80000000 0x00000000 0x80000000>;
        };

  • 0 in reply to Bin Liu
    Intellectual 400 points

    Bin,

    Yes, I made those modifications:

  • 0 in reply to Jim Meyer
    Intellectual 400 points

    Bin,

    I noticed the following new .ssh folder in the root directory after using the create_sdcard.sh script.  I didn't see this with the WIC file. Any issue?

    Also, when I login I get the following...  There are a few more of them with the create_sdcard.sh and v10 than with the WIC file and v9.

    Any issue?

  • 0 in reply to Jim Meyer
    TI__Guru**** 152541 points
    Jim Meyer said:
    I noticed the following new .ssh folder in the root directory after using the create_sdcard.sh script.  I didn't see this with the WIC file. Any issue?

    No issue. The folder is empty.

    Jim Meyer said:
    Also, when I login I get the following...  There are a few more of them with the create_sdcard.sh and v10 than with the WIC file and v9.

    They are fine too.

  • +1 in reply to Bin Liu
    Intellectual 400 points

    Bin,

    OK! Great!